Feeding apparatus for pilger mills



March 1940- A. VAN DEN'BUNGELAAR 2,192,808

FEEDING APPARATUS FOR PILGERMILLS Filed March 22, 1938 INVENTOR. fl/Fml van amfiuqge/aar vmyg v a WW)- A TTORNEYS.

Patented Mar. 5, 1940 FEEDING APPARATUS FOR PILGEB MILLS Alfred vanden Bungclaar, Amsterdam, Netherlanda'assignor to Tube Reducing florporation, New York, N. Y., a corporation or Delaware Application ch 22,

This invention relates to feeding apparatus for pilger rolling mills, particularly mills adapted for cold pilgering. Usually in such mills, the rolling action takes place in steps, that is, the article being rolled, for example, a tube or rod, must be fed forward to the pilger rolls in successive steps. Depending on the type of pilger mill used, there may be further motions in addition to the step-by-step feeding movement. When pilger rolls having fixed axes are employed, the article being rolled, i. e., the workpiece, must have a longitudinal reciprocation in the direction of the rolls, the article being gripped by the rolls and moved in one direction, and returned to a forward position between the rolls when released from them. When pilger rolls which are mounted-on a reciprocating carriage are employed, it is not necessary for the workpiece to have a reciprocating motion, but it may be necessary in the case of a tube to move the tube relative to the supporting mandrel and to return the mandrel to a rearward position after a length of tube has been finished. But in both the fined roll mill and the reciprocating roll mill. the e requirements for the feeding motion emst, and dimculties are presented because only a very short time is permitted for the feeding operationin the newer type of cold pilger mills op-.

erating at to rotations per minute only 0.066 to 0.12 second being availablebecause the pilger rolls release the workpiece for the feeding action only during a time corresponding approximately to 60 of roll rotation, the release being kept as small as possible in order that the rolling stroke shall not be too small and the production consequently too limited.

Various feeding devices have previously been suggested, but they all have had certain disadvantages. One commonly used device has the disadvantage that regulation of the feed during rolling is altogether impossible, depending on the number of rotations of the mill, and not being subject to calculation. Another device which has been used does provide feed adjusting, but this device in common with the one mentioned above has the disadvantage that large masses of stock or mechanism are required to perform considerable movements in a relatively short time resulting in high accelerating and braking power requirements, and jerky operation. Moreover, the return movement necessitates special mechanism which must also participate in the jerky movement.

The purpose of the present invention is to overcome these disadvantages and avoid ierm 1938, Sfl'lai No. 197,370

(@i. dt-ldi movements incident to the sudden acceleration and stoppage of large masses. In particular, the invention provides for unlimited adjustment of the feed during the rolling action, not merely a few changes or steps, and also provides for effect- 5 ing the return movement by the use of the same parts which are employed for feeding.

According to one embodiment, the objects of the invention are accomplished by the provision of a threaded nut rotating on a feed spindle, the m nut being intermittently turned rearward on the spindle and pushed forward to carry the spindle with it by a power pushing device. Further objects and advantages of the invention will be apparent to those skilled in the art from a consid- 15 eration of the accompanying description of an illustrative embodiment taken in connection with the accompanying drawing in Which:'

Fig. 1 is a side elevation of a pilger mill having reciprocating rolls and embodying the im- 20 proved feed device;

Fig. 2 is a central vertical section of the left or rear portion of Fig. 1;

3 is-a top plan view of the parts shown in Fig. 2; and 25 Fig. 4 is an enlarged view corresponding to a portion of Fig. 2, but showing a slightly modifled mechanism.

Referring to the drawing, the main gears A and B actuate a driving rod C connected 30 to the roll or rocker carriage D adapted to move to and fro on the ways or rails E. The rolls F may be co-ordinated in their movement by suitable gears cooperating with one or more gear racks G. The pinion for one of the rolls is indi- 35 cated by the reference character H. On a long slide bed J there runs a clamp device K for bolding the workpiece or stock L. A spindle M serves to feed the clamp and workpiece. The mechanism for operating this spindle to feed the workpiece 49 or stock is disposed in the housing N, and is shown in detail in Figs. 2 and 3. r

In the present instance, the spindle M is not rotatable, butis slidable through splined sleeves l and 2 secured in the walls of the housing N. do Between the walls of the housing a rotatable threaded not 3 is placed upon the spindle M. Adjacent the spindle, within the housing N, there is provided a constantlyrotating shaft 4 driven from the main power drive and provided with a 59 cam 25. The com operates a lever 7 through a cam follower roller 8, the lever 1 moving about a pivot t. A spring 9 continuously presses the roller 8 against the cam 5. The upper end of the lever l is disposed adjacent one face or the nut 55 3 for pushing the same forward when the lever is released by the cam. The nut is rotated rearwardly during the same time that the cam is moving the lever l rearwardly. The nut 3 may be rotated in any suitable manner. As illustrated, it is provided with gear teeth and meshes with a gear ll which is loosely mounted on the shaft of a motor 12. Means are provided for selectively driving the gear I slowly in the direction' to feed the stock and rapidly in the reverse direction to return the spindle to a rearward position. For rapid or return drive, a clutch I5 is operated to connect the gear H directly with a gear l3 keyed to the motor shaft. For slow or feeding drive, a clutch I8 is operated, the clutch l5 being disengaged at the same time, to operate the gear I4 from a gear 22 loosely mounted on the motor shaftand driven from the gear l3 through a reduction gear train, including gears l1 and IS on a first jack shaft and gears l8 and 2| on a second jack shaft.

The apparatus as thus far described operates in the following manner: By the rotation of the cam 5 in the direction of the arrow, the lever l is suddenly released after the roller 3 on the lever has passed over the highest point of the cam, so that the spring 3 causes the lever II to push the nut 3, and with it the spindle M and the workpiece L in feeding direction. The forward movement of the nut 3 is limited by'a fixed stop 23 which might be integral with the guide member 2. The longitudinal movement provided for the nut 3 between thestop 23 and the lever I when in its rearmost position, that is, the position where the roller 3 on the lever is disposed on the highest point of the cam 3, produces the maximum feed which the device can effect. From this maximum value the feed can be regulated without steps, that is, by an indefinite number of gradual increments, to 'zero.

After the nut 3 has been moved forward against the stop 23 by the lever I, the nut continues to turn through the action of the pinion gear l4 which is connected for normal feeding operations by the clutch l3 to the slow movement gear 22. This continued rotation tends to back the nut 3 away from the stop 23, but as the cause a slight additional feed of the spindle M r and stock workpiece L. If the spring is too weak the nut will push the lever I back without additional feed. By feed is meant the increment of length of stock which is moved forward intermittently to the reducing devices. This may be referred to as an absolute movement of the stock as distinguished from reciprocation found in the more orthodox type of pilger mills. As in practically all machines of the pilger type, the feed occurs while the stock is released between attacks of the rolls or rockers. The nut by continued rotation will be moved on the spindle M in the rearward or anti-feeding direction while the lever is also moving rearwardly. It will thus be seen that the number of rotations of the motor i2 during a predetermined period of time determines the extent to which the nut will be moved rearwardly on the spindle beforethe next forward movement of the lever I, and hence determines the amount of feed. When the speed of rotation of the nut 3 is such that it moves rearward with a speed equal to the speed of the lever i under the action of the cam 3, the nut will be in contact with the lever when the latter reaches its rearmost position and the maximum feed stroke will be obtained. But if the nut 3 turns more slowly, i. e., if it moves more slowly in the rearward or anti-feed direction (toward the left in Fig. 1) than the lever I, then the lever at the moment of its release will not immediately come in contact with the nut 3, but must first move forward a certain distance to engage the nut. The feeding stroke is thus shorter than previously when the nut had moved a greater distance while the lever was being moved back.

Any suitable means R (Fig. 3) may be employed for regulating the speed 'of the motor l2. For example, the motor may be poly-adjustable and provided with resistances; or it may be connected with the main driving motor through Leonard connections, as the number of rotations of the motor l2 naturally depends on the main drive because of the cam 6. Should one desire to obtain a fixed feed independently of the speed or the number of rotations of the machine, the driving of the nut throught the regulating motor might be eliminated and the nut instead be driven through the main drive of the machine. However, since for the rapid motion of the workpiece clamp K, particularly the return motion, a special motor is necessary, it is simpler to use this motor as described for the regulation of the feed.

By driving the nut from the regulating motor l2 the speedy return of the spindle is obtained by suitable changes in the gear connection. By connecting the clutch l5 and disconnecting the clutch It, the nut 3 will be turned to move it forward against the end of the stop 23 to force the spindle M, the stock clamping device K, and the workpiece or stock-L to the left, that is in the anti-feed or rearward direction.

Since the spindle nut 3 rotates constantly under the action of the motor drive, it would normally encounter friction during the time it is pressed against the stop 23. In order to avoid this, anti-friction means such as the roller bearing 24 and the interposed disc 25, as shown in Fig. 4, are provided. If desired also anti-friction means such as the roller bearing 28 and the interposed disc 21 may be placed between the other face of the nut and a reaction member slidably placed on the spindle and connected with the end of the lever ll.

' While certain specific embodiments of the invention have been illustrated and described, it is to be understood that the invention may be variously embodied within the limits of the prior art and the scope of the subjoined claims.

I claim:

1. Feeding apparatus for pilger rolling mills for feeding increments of length of stock to the rolls, comprising in combination, stock holding means, an intermittently operating device for feeding stock forward to the rolls, and constantly operating means cooperating therewith which moves back a predetermined extent relative to said stock holding means for each stroke of said intermittently operating device, said intermittently operating device acting upon and through said constantly operating means.

2. Feeding apparatus for pilger rolling mills for feeding increments of length of stock to the rolls, comprising in combination, a longitudinal member connected to the stock to be rolled, a

reciprocating feeding device movable along said amaeos rearward position, an element mounted on said member for cooperating with said device for moving the member forward, and means for moving said element rearwardly when said device moves rearwardly.

3. Feeding apparatus for pilger rolling mills for feeding increments of length of stock to the rolls, comprising in combination, a stock holding means, a constant stroke feeding device actuated intermittently in feeding direction, a member moving continuously against feeding direction relative to said stock holding means ,and cooperating at intervals with said feeding device for feeding the stock, and means for varying the speed of movement of said member for varying the amount of feed.

4. Feeding apparatus for pilger rolling mills for feeding increments of length of stock to the rolls, comprising in combination, stock holding means, a constant stroke feeding device actuated intermittently in feeding direction, a member moving continuously against feeding direction relative to said stock holding means and cooperating at intervals with said feeding device for feeding the stock, and means for varying the speed of movement of said member for varying the amount of feed, said speed varying means having a large number of gradual speed-change adjustments.

5. Feeding apparatus for pilger rolling mills for feeding increments of length of stock to the rolls, comprising in combination, stock holding means, a constant stroke feeding device actuated intermittently in feeding direction, a member moving continuously against feeding direction relative to said stock holding means and cooperating atintervals with said feeding device for feeding the stock, and means for varying the speed I of movement of said member for varying the amount of feed, said speed varying means comprising a drive motor device having means for varying the speed of said motor device in a lar number of small increments.

6. Feeding apparatus for pilger rolling mills for feeding increments of length of stock to the rolls, comprising in combination, a feed spindle, a reciprocating feed device, a member threaded on said spindle for cooperating with said feed device, means for turning said member slowly on said spindle as a measure of the feeding action, and means for turning said member rapidly in the reverse direction to return said spindle to a rearward position.

7. Feeding apparatus for pilger rolling mills for feeding increments of length of stock to the rolls, comprising in combination, a feed spindle, a constantly turning feed nut thereon, said nut having a variable range of movement during a unit of time, and a reciprocating feed device cooperating with said nut having a range of movement greater than the greatest movement of said nut reverse direction on said spindle, means for vary-.

ing the speed of said nut on said spindle, and a forward stop for said nut.

9. Feeding apparatus for pilger rolling mills for feeding increments of length of stock to the rolls, comprising in combination, a threaded spindle, a nut threaded thereon, a lever for pushing said nut and spindle in feeding direction, resilient means constantly urging said lever in feeding direction, a constantly rotating cam for moving said lever in reverse or anti-feed direction, continuously acting means for moving said nut in reverse direction on said spindle, means for varying the speed of said nut on said spindle, and anti-friction means disposed between said nut and said step.

' A. v. m'BUNGELAAR. 

